Mechanical Properties and Impact Resistance of Concrete Pavement Containing Crumb Rubber

Abstract

Concrete pavements are nowadays winning increasing attention although their use is still limited by the high stiffness or low flexibility of concrete. In addition, worn tires cause environmental problems and also have an inherent ability to absorb energy. Therefore, it is necessary to improve concrete flexibility and energy absorption capacity by adding recycled materials such as crumb rubber. For this study, impact resistance and damping coefficients were investigated as the parameters affecting the energy absorption capacity of pavement concrete as well as the compressive, flexural, modulus of elasticity, and density of rubberized concrete. Crumb rubber 0–5 mm in diameter was replaced in concrete mixes for fine aggregate at volume ratios of 0%–60% (about 25% of total aggregate volume). The numerical models were used for validating laboratory results of damping tests, showing a good agreement between laboratory and numerical model frequencies. Moreover, the influences of geometrical property, as well as crumb rubber content, on the first frequency parameter of the samples were scrutinized by employing the finite-element model. Based on the results obtained, the replacement of 60% crumb rubber led to an increase of about 75% in impact resistance required for the first crack to appear and an increase of about 170% required for the specimen to fail. The damping coefficient of the concrete containing 60% crumb rubber also increased from 2.35% to 4.19%, indicating the significantly enhanced energy absorption capacity of the concrete containing crumb rubber. However, the specimens exhibited reductions of about 32%, 36%, 43%, and 21% in compressive strength, flexural strength, modulus of elasticity, and density of concrete, respectively, as a result of crumb rubber addition.